Conventionally, among game machines, pachinko game machines are endlessly subjected to deceit actions in which prize balls are unfairly obtained, and various preventive measures have been taken. For example, if an abnormality has occurred in a pachinko game machine, the game player alerts the abnormality to a staff in the amusement center by pressing a call button and the like. The staff, who has been alerted to the abnormality, unlocks the pachinko game machine by a key and takes any measures to the abnormality. A pachinko game machine includes a wooden frame fixed to a game machine placement island, a main body frame for holding a game board, and a glass frame for holding a glass plate that protects a surface of the game board. The main body frame is opened and closed from the wooden frame, and the glass frame is opened and closed from the main body frame. In this type of known pachinko game machine, the main body frame and the glass frame are opened and closed by one and the same key. There are cases where, among game players, people who are named as Goto-shi unfairly acquire said key and make deceit actions, such as opening the glass frame using the key while staffs do not see them and putting game balls into various win holes on the board surface of the game board so as to acquire a large number of game balls, or opening the main body frame and replacing the ROM into an unauthorized one, or the like.
In order to prevent such deceit actions by an unfair use of the key, preventive measures have been taken such as providing an electric lock to a pachinko game machine, fixing a ROM by a wire to avoid the ROM from being replaced into an unauthorized one even when the main body frame is opened, or the like. In addition, visual monitoring is performed using a monitoring monitor provided in the amusement center. Further, it is also controlled when the key has been taken out of the key storage box and when it has been returned thereto.
However, in the monitoring using the monitoring monitor, whether or not deceit actions have been made is determined by human beings by checking images on the monitor. Therefore, there is high possibility that the deceit actions are overlooked. If frames of a plurality of pachinko game machines have been opened, the possibility of overlooking the opened state further increases. Checking the recorded images on the monitor takes much time. Even if the key is controlled, it is impossible to know who has used the key for which pachinko game machine, and it is difficult to trace or prevent deceit actions.